R. J. -F. Tsai et al. (NEJM 343:86 (2000), I. R. Schwab et al. (Cornea 19:421 (2000) and G. Pellegrini et al. (The Lancet 349:990 (1997)) describe transplanting limbal stem cells for diseases arising from limbal stem cell deficiency to restore corneal epithelial integrity.
The Tsai paper mentions that conjunctival epithelial cells are an integral part of the eye surface, but Tsai et al. and other papers on limbal stem cell transplantation indicate that (i) the conjunctival and corneal cell types are quite different in function and morphology, with the limbal cells being the progenitor of corneal cells; and (ii) to achieve regeneration of the corneal surface, the important stem cell type to transplant is the limbal stem cell. Tsai et al. and others fail to suggest that conjunctival epithelium is useful in restoring the corneal surface. The limbal stem cell is indeed an important factor in restoring the corneal surface, but conjunctival stem cells are important in preventing limbal stem cell and corneal epithelial damage in the first place. This is due to the supportive function of conjunctival stem cells, which is important to regeneration and restoration of the ocular surface.
Z-G. Wei et al. (Investigative Ophthalmology and Visual Science 34:1814 (1993)) describe the origin of conjunctival stem cells at the fornix. Y. Diebold et al. (Graefe's Arch. Clin. Exp. Ophthalmol. 233:268 (1997)) describe primary culture of cells from forniceal conjunctiva tissue.